Lith-type emulsions with organosilicone block copolymers



United States Patent 3,294,537 M TH-TYPE EMULSIGNS WHTH ORGANOSHLHQUNE ELWIIK QGPQLYMERS Kirby M. Milton, Rochester, N.Y., assignor to Eastman Kodak Company, Rochester, N.Y., a corporation of New Jersey No Drawing. Filed Sept. 17, 1965, Ser. No. 4558,244 23 Claims. (Cl. 96-67) This invention relates to photography and particularly to improved photographic silver-halide emulsions of the lith-type.

Photographic films used in the graphic arts for making halftone or line images should be capable of producing extremely high contrast and good image sharpness. These factors contribute in the case of half-tone images to high dot quality, that is, to the production of halftone dots of high density and sharpness.

Photographic elements of the lith-type typically comprise fine-grain, high-contrast silver halide emulsions whose halides contain at least 50 mole percent chloride, and which are processed customarily in alkaline hydroquinone developing solutions having very low concentration of free sulfite ion in order to produce the high contrast and high dot quality required for good quality halftone reproduction. Such developing solutions are unstable, having very short tray or tank life during exposure to air, so the solutions must be prepared fresh before they are to be used for processing.

Common photographic lith-type materials are deficient with respect to exposure and development latitude when such materials are processed in preferred lithographic developing solutions which contain low concentrations of sulfite ions. This deficiency causes the contrast and halftone dot quality of the image reproduction to be overly sensitive to development time. It also is manifested in a nonlinearity in the relationship between effective film speed and development time, causing unequal increases in effective film speed with equal increases in development time.

Advantages are gained by increasing the contrast and quality of lith-type" emulsions by the use of high molecular weight polyethylene glycols, coupled with development in low-sulfite, pure hydroquinone developers.

In films containing polyethylene glycols and their derivatives, however, optimum quality is obtained over only a rather restricted development time range and at the sacrifice of efiective speed. When the quantity of polyethylene glycol is increased, optimum dot quality is obtained over a broader development time range, but only with a concomitant decrease in effective film speed, emulsion hardness and evenness of development. Evenness of development is the property of an exposed photographic material to maintain good efiective contrast and good halftone dot quality over a relatively wide range of development time.

With or without the use of polyethylene glycols, it has in the past been necessary to use pure hydroquinone developers of low free-sulfite ion content in order to obtain the high contrast and halftone dot quality desired. Such developers are unstable because of aerial oxidation of the developing agent in alkaline solution. If the sulfite level is increased to prevent this oxidation, the desired contrast and dot quality of the processed photo graphic material are lost. Hence, it has been necessary either to prepare the developing solution fresh or to use two solutions which are mixed just before use, one of which contains hydroquinone in a mildly acidic solution buffered to a low free-sulfite level with a sulfite donor, and the other of which contains alkali. Even so, such solutions are stable after mixing for only a limited time ice in a tray or a tank due to aerial oxidation of the developing agent.

It would be desirable to have an improved lith-type photographic material which is advantageously developable in a more stable developing solution, and which, when processed in such solutions, exhibits good contrast and halftone quality over an extended range of development time and permits obtaining equal increases in effective speed for a given increase in development time.

I have found that the addition of certain water-soluble organosilicone block copolymers to chlorobromoiodide emusions increases speed of development, contrast and halftone quality and that these increases are found over a greater development range than that afforded by the use of polyethylene glycols. Regardless of the concentrations of the silicone compounds of my invention used and regardless of the developing times used within a wide range, the increase in speed is found to be constant for a given increase in development time. Furthermore, by the use of these materials, suflicient free sulfite ion can be added to the developer to give a stable single solution; yet the contrast and halftone dot quality are as high as normally seen in emulsions containing polyethylene glycol and developed in a low sulfite, hydroquinone developer.

It is, therefore, an object of my invention to provide a photographic film which produces high contrast and high halftone dot quality even when developed with a developer solution having sufiiicently high free-sulfite content to insure good stability upon prolonged exposure to air in tray or tank.

Another object is to provide a photographic element which is capable of producing high contrast, high quality halftone images over a relatively broad range of film exposure and development times.

Another object is to provide a photographic element which develops evenly.

Still other objects will become apparent from the following specification and claims.

These and other objects are accomplished according to my invention by the use of photographic elements comprising a support, at least one hydrophilic colloidal fine-grain photographic silver halide emulsion layer whose halide is comprised of at least mole percent of chloride, and either contiguous to the silver halide or integral therewith, certain water-soluble silicone-containing polyalkylene block polymers.

Water-soluble organosilicone polyalkyleneoxide polymers used to advantage according to my invention include those disclosed in US. Pa'tent No. 2,917,480, issued December 15, 1959, assigned to Union Carbide Corporation.

Polymers used advantageously according to my invention are of the type which are prepared by reacting a diallcyl siloxane with a compound of the following structure:

wherein Y is an organic radical having a valence of x, and wherein n is an integer, x is an integer greater than 1, the values of n and x are such that the molecular weight or the compound, exclusive of E, Y and R is between 800 and 3,000, and E is a polyoxyethylene chain constituting about 1070 percent by weight of the compound, R is a hydrogen atom or the residue of an organic compound containing an active hydrogen atom, such as, an alkyl, carbonyl, or aryl carbonyl group, e.g., alcohols, amines, acids, amides, phenols, etc. The conventional alkaline, pure hydroquinone, low free-sulfite developer may be used to develop my exposed element. It is also advantageous to use a developer having from 10 to about 30 grams of an alkali sulfite per liter of the developer solution. When my elements are developed in the preferred developer solutions, not only is the image contrast high and the dot quality excellent but this excellent quality is produced over a wide range of exposures and development times.

My elements are particularly valuable when developed with a stable dihyd-roxybenzene developer with a high free sulfite ion concentration in an alkaline solution. My elements provide the following advantages:

(1) More even rate of speed change with changes in development times which allows varying the development time systematically to control speed without sacrificing quality;

(2) Better dot quality over a wider range of development times and temperatures;

(3) Elimination of or reduction in development defects, such as, drag lines when the materials are developed in automatic roller transport processing equipment;

(4) High contrast and much better dot quality when stable developer solutions containing a high free-sulfite concentration, e.-g., 10 to 30 grams of an alkali metal sulfite per liter of solution are used;

(5) Increased speed without loss of dot quality when an onium salt is incorporated in my light-sensitive emulsion layer, and still further advantages will be apparent from the specification and claims. It is unexpected that the immediate organosilicone block polymers would produce the above cited advantages since other silicone-containing chemicals are known to have detrimental effects on photographic silver halide emulsions.

The organosilicone block polymers used according to my invention are water soluble and are advantageously added in a water solution to the aqueous hydrophilic colloid (either with or without the silver halide) before it is coated. The organosilicone block polymers are used to advantage over a wide range of concentrations. The

operable range of concentrations is from .001 to 1.00 gram of block polymer per mole of silver, while the preferred range is from 0.010 to 0.200 gram per mole of silver. The optimum concentration of a given block polymer used in my elements depends upon the results desired, the particular silver halide emulsion, the developer solution, etc., and is readily determined by methods well known in the art. The determination of the optimum concentration is preferably made by employing the organosilicone block polymer in the silver halide emulsion layer or in an adjacent hydrophilic colloid layer according to the element that is desired.

Typical fine grain silver halide emulsions used to advantage can be prepared as described by MacWilliam US. 2,756,148 issued July 24, 1956. These emulsions may be used without being sensitized; however, it is advantageous to spectrally sensitize them according to methods well known in the art to make them orthochromatically-sensitized or panchromatically-sensitized.

The silver halide is dispersed in hydrophilic colloid materials used as binders, including gelatin, collodion, gum arabic, cellulose ester derivatives, such as alkyl esters of carboxylated cellulose, hydroxy ethyl cellulose, carboxy methyl hydroxy ethyl cellulose, synthetic resins, such as the amphoteric copolymers described by C'lavier et al. in US. Patent 2,949,442, issued August 16, 1960, polyvinyl alcohol, and others well known in the art. Examples of these polymeric gelatin substitutes are copolymers of allylamine and methacrylic acid; copolymers of allylamine, acrylic acid and acrylamide; hydrolyzed copolymers of allylamine, methacrylic acid and vinyl acetate; the copolymers of al=lylamine, methacrylic acid and acrylonitrile; alkyl acrylate-acrylic acid copolymers, e.-g., copolymers of butyl acrylate-acrylic acid; etc.

When my organosilicone block polymers are incorporated in a layer adjacent to the silver halide emulsion layer instead of in the light-sensitive layer, any of the hydrophilic colloids described hereinbefore may be used to advantage as a binder for coating my polymers.

It is advantageous to add certain onium salts, such as,

quaternary ammonium salts, sulfonium salts and phosphonium salts to my light-sensitive emulsions in order to increase the photographic speed without adversely affooting the improved dot quality, contrast and evenness 5 of development. Examples of quaternary ammonium salts include nonyl pyridinium perchlorate, hexoxymethyl pyridinium perchlorate, ethylene bis-dioxymethyl pyridinium perchlorate and others described by Carroll U.S. 2,271,623, issued February 3, 1942, hexadecamethylenel,l6-bis(pyridinium perchlorate), 9,16 diaZa-7,18-dioxa- 8,17-dioxotetracosane 1,24 bis(pyridinium perchlorate), and others of Beavers et al. US. 2,944,898, issued July 12, 1960. Other examples include the onium salts of polyoxyalkylenes of Carroll et al. US. 2,944,902, issued July 12, 1960, the polyonium salts of Carroll et al. US. 2,288,226, issued June 30, 1942, such as bis(lauryl methyl sulfonium p-toluene sulfonate) 1,2-ethane, N,N'-trimethylene dioxymethyl pyridinium perchlorate, etc., the sulfonium salts of Carroll et al. US. 2,275,727, issued March 10, 1942, such as n-decyl dimethyl sulfonium ptoluene sulfonate, n-nonyl dimethyl sulfonium p-toluene sulfonate, etc., and the phosphonium salts of Carroll et al. US. 2,271,622, issued February 3, 1942, such as tetramethylene bis-triethyl phosphonium bromide, lauryltriethylphosphonium bromide, etc.

My light-sensitive emulsions can be coated to advantage on any of the conventional photographic supports, including glass, cellulose acetate, polystyrene, polyalkyleneterephthalate, etc. The organosilicone block polymers can be coated advantageously in the silver halide emulsion layer or in a hydrophilic colloid layer that is either under or over the silver halide emulsion layer so that the block polymer is contiguous to the silver halide.

Included among the organosilicone block polymers used to illustrate my invention are those which may be prepared by reacting a polypropylene oxide-polyethylene oxide block polymer with dimethyl siloxane to give a copolymer having the following general structure:

wherein a and b are positive integers, M is a polyethyleneoxy chain constituting approximately 10-70% by weight of [(M),,(N) N is a polypropyleneoxy chain having a molecular weight between approximately 800 and 3000, and wherein x, y and n arepositive integers as shown in Table A.

TABLE A Compound Percent Silicon Ratio 11:1 11.

were exposed on an intensity scale sensitometer and proopment rate. The following tables illustrate this advancessed in a developer of the composition: tage. These coatings were made and processed as de- G. scribed in Example I. Hydroquinone 15 TABLE II (a) Sodium formaldehyde b1sulfite 50.0 Sod um carbonate 35.0 Change in Sodium bicarbonate 22.5 Relative Sodium sulfite 2.5 f gf Compound g 'g g gg f Potassium bromide 0.75 Develp Water to make 1.0 l. mm Tune 3 o for 44 minutes at a temperature of 68 F., fixed in a oleylether PEG (see EX 12 713 conventional sodium thiosulfate fixing bath, Washed and CompoundAofTableA 0.06 170 dried. The polymers, their concentration in each coating as well as speed, effective contrast and dot quality of the TAB LE 11 0 Mol. Wt. Change in Coatlng Gm./Ag of PPO Percent Percent relative speed No. Compound mole Block PE G Si over a 3 min.

Development Time Oleyl ether of PEG (see Ex. l) .125 100 877 Organoxilicone .200 2,300 10 4. 5 134 do .200 2,300 10 9.0 129 processed coatings and evenness of development that were obtained are summarized in Table I.

TABLE 1 Coating Gm./ Rel. Efiective Halitone Evdnness No. Compound Ag Speed Contrast Dot of Developmole Quality-f menti None 102 6.4 1 .08 PEG .125 100 7. 0 3 .205 Cpd. B of Table A 030 67 14. 5 7 035 Cpd. C of Table A- .040 74 11.3 7 .010 Cpd. D of Table A t .050 63 12. 7 7 025 Cpd E of Table A-.." .050 53 12. 0 8 .005 'Cpd. F of Table A .040 42 11.3 8 .055 Opd. G of Table A. .060 76 10.0 0 .02 Cpd. H of Table A 030 05 13. 0 7 03 Cpd I of Table A .030 48 13. 0 7 .00 Organosilicone I (2.... .120 37 16.0 9 .07 Organosilicone II 100 53 13. 1 7, 06

Organosilicone l: and polyether sections containing 6.5% by Weight of silicone.

PE G: Oleyl ether of polethyleneglyeol having a molecular weight of 1,540.

A water-soluble polysiloxane composed of dimethyl silicone sections Organosilicone II: A water-soluble polysiloxane composed of dimethyl siloxane sections and block polymers of ethylene oxide and propyleneoxide, containing 8.2% by weight of silicone.

*Efi'ectivc Contrast in the tables is determined by drawing a straight line between the net optical densities of 0.1 to 2.4 on the net optical density v. logarithm of the exposure plot and taking the tangent of the angle formed between the straight line and the log exposure axis.

TTlalitone Dot Quality-Dot quality is a measure of the quality of the reproduction of a halltone image. and developed, highlight areas.

The

dot quality used herein is a measure of the areas referred to as dots (i.e., clear and developed density) and is expressed extremely poor. A dot quality below 6 is generally not acceptable.

in a progressive scale where 9 is excellent and l is iEvenness of DevelopmentIdeally, the rate of change in the log of the speed with constant; that is:

change in development time should equal a log speed at time t=K log speed at time [t 1] When the rate of change in the speed is plotted against the development time, the slope Evenness of dcoi the resultant curve will approach 0 as K approaches a constant value.

In Table I, evenness of development The smaller the number, the more even the development, inbetween the sensitometrie curves obtained for equal diilerences velopment is the slope of the plot of is expressed in this way. dicating more even spacing in development time.

The data in Table I show that my lith elements containing organosiliconeblock copolymers produced good image contrast, good dot quality, and good evenness of development. The element outside my invention, i.e., those containing oleyl ether of polyethyleneglycol produced very poor dot quality, poor contrast and very poor evenness of development.

Example II By varying the concentration of the water-soluble polyalkylene oxide-dialkyl siloxanes, it also is possible to make materials having relatively small changes in speed with development time. This characteristic is particularly advantageous in automatic processing equipment where the activity of the developer may vary with aging or other variables may be present which affect the devel- K against time.

Example III The coatings in the following examples were prepared like those previously described and were processed in a high sulfite pure hydroquinone lith developer of the following type which is more stable to oxidation than the low uulfite developers normally used, but which usually gives poorer dot quality.

HIGH SULFITE DEVELOPER E 0 to 1000 cc.

7 The results tabulated in Table III below show how the dot quality is maintained better over the entire tonal scale when a water-soluble polypropylene oxide-dialkyl siloxane is added to the emulsion compared to the results obtained with a simple polyethylene oxide polymer.

however, that the addition of an onium salt to the emulsion will increase the speed without adversely ailecting the improved dot quality and contrast obtained from the addition of the preferred copolymer. The coatings in this example were processed for 2% minutes in the devel- This comparison also shows that the silicone polymer oper of Example I.

' TABLE v Coating Oniuin Salt Gin/Ag Relative Effective Dot No. mole Speed Contrast Quality 1 None 100 8.9 8 2 N,Nethylenedioxyn'iethyl .066 302 13.0 8

ridiniuin perchlorate.

gives results better than those obtained with alkyleneoxide It can be seen from the above results that the addition block copolymers not containing silicone. The developof the quaternary ammonium salt increased the speed of ment time was 1% minutes. the emulsion by about 300 percent with no loss in dot T BL In quality or contrast. Other onium salts, such as the A E quaternary ammonium, sulfonium, and phosphonium D t Qu salts, described in US. Patents 2,271,622, 2,275,727, 2,288,226, 2,944,898, 2,271,623, and 2,944,902 can be Coatin Pol iner A t No. L! Y s High 50% Shadow used W1 h imilar results gght; Dots Dots Example VI ots 5 An emulsion as described in Example I was divided PEG n5 6 6 6 2 into two portions one of which was retained as a control, Block DCIVI I'ICIZTIII 1020 7 7% 714 while to the other portion were added, per mole of silver orgmllslncone n 7 8 8A halide, .200 gm. of the organosilicone I of Example 1. Both portions were then coated and processed according Polyethyleneglycol of Example 1. 3 A copolymer composed of blocks of polyethylene oxide to the procedures In Example I and poly propyleneoxide having a total molecular weight of The results are shown in Table VI. 2,000 and wherein the ratio by weight of said blocks is 60 to 40, respectively. TABLE VI Organosilicone II (see Example I).

Example IV Efiective Contrast Dot Quality I Dev. Time Fog The coatings in this example were prepared like those Control Sam 16 1 Contr 1 Sam 1 1 previously described and were processed in the developp0 ing solution of Example I. The results tabulated in Table 8 0 10 0 6 8 0 01 IV below illustrate how the image quality obtained with 5 3 8 1 coatings containing a silicone-containing polyethyleneoxy -2 12-3 1 8.8} copolymer remains good over a long development range 1 1 and that it is better than that obtained with the related block copolymer from which it was synthesized.

Control plus organosiliconc I of Example I.

l TS=too slow.

TABLE IV Dot Quality for Various Coating GrnJAg Dev. Times in Min.

No. Polymer mole 1 Block Copolyrner of Ex. III (9 0.020 8% 8A 8 6% 2 Compound I of Table A G) 025 9 9 8% 8 (9 Compound I oi Table A was synthesized from the Block Copolymer of Example III and a siloxane.

Example V The following example illustrates the improvement obtained from the addition of a quaternary ammonium salt to a high-contrast silver chlorobromide emulsion containing 10 gm. of a water-soluble polyalkylene-oxideinto equal parts. One was retained as a control and to dialkyl siloxane (organosilicone II of Example 1). While the others were added the compounds as listed in Table these polymers give an improvement in dot quality and VII. Each sample was coated and tested as in Examcontrast, they tend to reduce speed. It has been found, pie I. The results obtained are shown in Table VII.

TABLE VII Etl'ective Contrast Dot Quality Fog Development Time Control 7. 9 e. 2 r. 0 5 Control plus oleyl ether of Ex. I 12. 0 13. (J 8 2 g 5 i l Control plus Silicone I of Ex. I (5 13. 0 16 16 9. 0 8 9 8 6 0 01 Control plus Silicone I of Ex. I (7 16 16 16 16 8 9 9 7 0 01 Control plus Silicone I oi Ex. I (1 15.5 16 16 16 8 9 9 7 0 01 Control plus Silicone I of Ex. I mg 13. 5 16 16 10 1 TS 9 9 8 001 Control plus Silicone I oiEx. I mg) 13.0 16 10 16 1 TS 9 9 8 0 01 1 Control plus or gaiiosilicoue I of Exam lo I. 1 lS=too slow. p

Example VIII This is a repeat of Example VII. The results are recorded in Table VIII.

19 The following additional examples illustrate the useful molecular weight ranges and polypropylene oxide/polyethylene oxide ratios of the polyalkylene oxide-dialkyl siloxane polymers.

Example X In each case, the polymers were add-ed to separate portions of a silver chlorobromoi-odide emulsion containing approximately 90 mole percent chloride, 9 mole percent TABLE VIII Effective Contrast Dot Quality Fog Development Time 1.75 2.75 3.75 4.75 1.75 2.75 3.75 4.75 4.75

Control 7. 5 6.1 6. 3 6.4 6 4 1 1 0.01 Control plus oleyl ether of Ex. I (50 mg 10.5 7. 5 5. 5 5. 8 7 3 l 0.01 Control plus oleyl ether of Ex. I (100 mg 12. 16 14.0 9. 0 8 8 5 3 0.01 Control plus oleyl ether of Ex. I (125 mg 9. 5 16 16 9. 5 7 8 6 3 0.01 Control plus oleyl ether of Ex. I (150 mg 11.8 15.0 16.0 13.0 8 9 6 4 0.01 Control plus oleyl ether of Ex. I (200 mg.) 8.2 16 16 13.2 7 9 8 5 0.01 Control plus Silicone I of Ex. I (50 mg.) 7. 5 6. 8 5.8 5.1 7 3 2 1 0.01 Control plus Silicone I of Ex. I (100 mg.) 16 15.5 16 16 8 8 8 7 0.01 Control plus Silicone I of Ex. I (125 mg.) 16. 0 16 16 16 7 8 8 7 0. 01 Control plus Silicone I of Ex. I (150 mg.) -1 16 16 16.0 16 8 9 9 8 0.01 Control plus Silicone I of Ex. I (200 mg.) 13. 5 16. 0 16 16 1 TS 9 9 9 0.01

1 TS=too slow.

It is shown that at comparable concentrations of a polybromide, and 1 mole percent iodide. The emulsions were ethyleneglycol and an organosilicone, the latter maintains coated on a polyalkylene-terephthalate film support at a a superior quality with respect to effective contrast and coverag of 455 Silver and 450 of gelatin P halftone dot quality. square foot. Samples of each coating were exposed on an E 1 IX intensity scale sensitometcr and processed in the dexamp e veloping solution of Example I for 4% minutes, fixed, A coating containing 75 mg. of the organosilicone II washed, and driedlwith the indicated results. See Table X.

TABLE X Mo]. Wt. Percent Percent MgJMole Rel. Eli. Halftone Evenness Sample Polymer of PPO PEO 1 Si AS Speed Contr Dot of Devel.

Block Quality 1 Polyethyleneglycol of Ex- 100 I. 125 100 6. 5 1 .20

ample I. Silicone polymer 1.. 20 6. 8 12. 1 9 06 Silicone polymer II. 10 20. 4 100 45 7. s 8 05 Silicone polymer III 10 4. s 50 11. 0 7 .07 Silicone polymer IV 2. 2 118 4. 8 2 27 Silicone polymer V-.. 40 3.7 100 5. 1 1 18 Silicone polymer VI 40 8. 5 100 97 4. 3 l 19 Silicone polymer VII 50 6. 9 50 87 4. 9 7 03 Silicone polymer VIII 50 6. 9 50 76 10. 0 8 06 Copolymer A 2 100 50 135 3.4 1 22 Copolymer B 2 100 50 123 2. 7 1 .09

l PEO=oleyl ether of polyethylene oxide, Mol. Wt.=1,540. 2 Copolymer A=copolymer of Carbowax 4000 and polydimethyl siloxane. Copolymer B=copolymer of Carhowax 1000 and polydimethyl siloxane.

3 Undetermined.

Results: Tile compound outside my invention, i.e., those contained in samples 1, 0, 7, l0 and 11 do not yield acceptable dot quality.

of Example I and a control containing mg. of the oleyl ether of polyethylene glycol per silver mole were each developed to optimum contrast in a developer containing a high level of sulfite ion of the following composition:

Control+silicone II of Ex. I I 12.2

It also has been found that the addition of saponin to silver halide emulsions containing polyalkylene oxidedialkyl 'siloxane polymers results in a large increase in speed without a loss of the beneficial effects produced by these polymers. This is unexpected in view of the fact that the addition of saponin to an emulsion containing a simple polyethylene glycol polymer produced only a minor speed effect and the addition of saponin to an emulsion in the absence of any polymeric material of this type produces no sensitometric effect.

The following example illustrates this synergism.

Example XI The following coatings were prepared and processed as described in previous examples. The coatings were developed for 3% minutes in the developing solution of Ex ample I.

TABLE X1 Coating Mg. Mg. Rel. E11. Evenness Number Polymer Polymer/ Saponin/ Speed Contr Fog of Devel- DQ 1 Ag mole Ag mole opment None None 100 2.0 01 07 1 do 3 5.1 89 2.8 .01 .07 3 0... 10.2 100 2.6 .01 .05 1 PEG 2 i None 100 12.8 01 .14 8 PEO 5.1 115 11.0 .01 .14 7 PEO Z 10. 2 141 10.0 01 15 7 Organosilicone I of None 100 9. 0 .01 07 Organosilicone I of Ex. I 5.1 159 12.2 .01 .02 9 Organosilicone I of Ex. I 10. 2 240 12. 0 01 01 8 2 PEO=oleyl etherof polyethylene oxide, M.W.=1540.

It will be appreciated that although the block copolymers of this invention are usefully incorporated in the photographic emulsion or in an adjoining insensitive layer, the block copolymers can be imbibed from a processing bath, it being required only that the block copolymer be present during development.

The invention has been described in detail with particular reference to preferred embodiments thereof, but it will be understood that variations and modifications can be effected Within the spirit and scope of the invention as described hereinabove and as defined in the appended claims.

I claim:

1. A photographic silver halide emulsion in which the halide comprises at least 50 mole percent chloride, said emulsion containing a block copolymer comprising blocks of polyoxyethylene and polyoxypropylene, about 10 to about 70%, by Weight, of said copolymer being polyoxyethylene and the average molecular weight of polyoxypropylene in said copolymer being in the range of about 800 to about 3,000, said block copolymer containing up to about percent, by weight, of silicon atoms in the main polymer chain.

2. A photographic silver halide emulsion in which the halide comprises at least 50 mole percent chloride, said emulsion containing about .001 to about 1 gram, per mole of silver halide, of a block copolymer comprising blocks of polyoxyethylene and polyoxypropylene, about 10 to about 70% by weight of said copolymer being polyoxyethylene and the average molecular weight of polyoxypropylene in said copolymer being in the range of about 800 to about 3,000, said block copolymer containing up to about 15% by weight of silicon atoms in the main polymer chain.

3. A photographic silver halide emulsion in which the halide comprises at least 50 mole percent chloride, said emulsion containing a polymer prepared by reacting a dialkyl siloxane with a block copolymer comprising blocks of polyoxyethylene and polyoxypropylene, about 10 to about 70% by weight of said copolymer being polyoxyethylene and the average molecular weight of the polyoxypropylene in said copolymer being in the range of about 800 to about 3,000, said block copolymer having the formula:

where Y is an organic radical having a valence of x; n is an integer; x is an integer greater than 1, the values of n and x being such that the molecular weight of said copolymer exclusive of Y, E and R is in the range of about 800 to about 3,000; B being a polyoxyethylene chain constituting from about 10 to about 70% by weight of said copolymer and R is a hydrogen atom, an alkyl group, an alkyl carbonyl group or an aryl carbonyl group.

4. A photographic silver halide emulsion in which the halide comprises at least 50 mole percent chloride, said emulsion containing about .001 to about 1 gram per mole of silver halide, of a polymer prepared by reacting a dialkyl siloxane with a block copolymer comprising blocks of polyoxyethylene and polyoxypropylene, about 10 to about 70% by weight of said copolymer being polyoxyethylene and the average molecular weight of the polyoxypropylene in said copolymer being in the range of about 800 to about 3,000, said block copolymer having the formula:

where Y is an organic radical having a valence of x; n is an integer; x is an integer greater than 1, the values of n and x being such that the molecular weight of said copolymer exclusive of Y, E and R is in the range of about 800 to about 3,000; E being a polyoxyethylene chain constituting from about 10 to about 70% by weight of said copolymer and R is a hydrogen atom, an alkyl group, an alkyl carbonyl group or an aryl carbonyl group.

5. A photographic silver halide emulsion in which the halide comprises at least 50 mole percent chloride, said emulsion containing about .001 to about 1 gram per mole of silver halide, of a block copolymer having the formula:

l ([3113 .Jx n

[( )a( )b]y wherein a and b are positive integers, M is a polyethyleneoxy chain constituting about 10 to about 70% by weight of wherein a and b are positive integers, M is a polyethyleneoxy chain constituting about 10 to about 70% by weight of N is a polypropylene chain having a molecular weight between about 800 and 3,000, and wherein x, y and n are positive integers, and n has a value of 1 to 8.

7. A photographic silver halide emulsion in which the halide comprises at least 50 mole percent chloride, said emulsion containing about .001 to about 1 gram per mole of silver halide, of a Water-soluble block copolymer having the following formula:

wherein a and b are positive integers, M is a a poly- 13 ethyleneoxy chain consistuting about to about 70% by weight of N is a polypropyleneoxy chain having a molecular weight between about 800 and 3,000, and wherein x, y and n are positive integers, and the ratio of xzy is from 2:1 to 1:1.

8. A photographic element comprising a support having thereon a photographic silver halide emulsion layer in which the halide comprises at least 50 mole percent chloride, said emulsion containing a water-soluble block copolymer comprising blocks of polyoxyethylene and polyoxypropylene, about 10 to about 70% by weight of said copolymer being polyoxyethylene and the average molecular weight of the polyoxypropylene in said copolymer being in the range of about 800 to 3,000, said block copolymer containing up to about percent by weight of silicon atoms in the main polymer chain.

9. A photographic element comprising a support having thereon a photographic silver halide emulsion layer in which the halide comprises at least 50 mole percent chloride, said emulsion containing a polymer prepared by reacting a dialkyl siloxane With a water-soluble block copolymer comprising blocks of polyoxyethylene and polyoxypropylene, about 10 to about 70% by weight of said copolymer being polyoxethylene and'the average molecular Weight of the polyoxypropylene in said copolymer being in the range of about 800 to 3,000, said block copolymer having the formula:

where Y is an organic radical having avalence of x; n is an integer; x is an integer greater than 1, the values of n and x being such that the molecular weight of said copolymer exclusive of Y, E and R is in the range of about 800 to 3,000; E being a polyoxethylene chain consituting from about 10 to about 70% by weight of said copolymer and R is a hydrogen atom, an alkyl group, an alkyl carbonyl group or an aryl carbonyl group.

10. A photographic element comprising a support having thereon a silver halide emulsion in which the halide comprises at least 50 mole percent chloride, said emulsion containing about .001 to about 1 gram per mole of silver halide, of a polymer prepared by reacting a dialkyl siloxane with a water-soluble block copolymer comprising blocks of polyoxyethylene and polyoxypropylene, about 10 to about 70% by weight of said copolymer being polyoxyethylene and the average molecular weight of the polyoxypropylene in said copolymer being in the range of about 800 to about 3,000, said water-soluble block copolymer having the formula:

where Y is an organic radical having a valence of x; n is an integer; x is an integer greater than 1, the values of n and x being such that the molecular weight of said copolymer exclusive of Y, E and R is in the range of about 800 to about 3,000; E being a polyoxyethylene chain constituting from about 10 to about 70% by weight of said copolymer and R is a hydrogen atom, an alkyl group, an alkyl carbonyl group or an aryl carbonyl group.

11. A photographic element comprising a support having thereon a photographic silver halide emulsion layer in which the halide is at least 50 mole percent chloride, said support having thereon at least one other layer, and incorporated in at least one layer of said element, a watersoluble block copolymer comprising blocks of polyoxyethylene and polyoxypropylene, about 10 to about 70% by weight of said copolymer being polyoxyethylene and the average molecular weight of polyoxy-propylene in said copolymer being in the range of about 800 to about 3,000, said block copolymer containing up to about 15% by weight of silicon atoms in the main polymer chain.

12. A photographic element comprising a support having thereon a photographic silver halide emulsion in which the halide comprises at least 50 mole percent chloride, said support having thereon at least one other layer, and incorporated in at least one layer of said element, about .001 to about 1 gram, per mole of silver halide, of a water-soluble block copolymer comprising blocks of polyoxyethylene and polyoxypropylene, about 10 to about 70% by weight of saidl copolymer being polyoxethylene and the average molecular Weight of polyoxypropylene in said copolymer being in the range of about 800 to about 3,000, said block copolymer containing up to about 15% by weight of silicon atoms in the main polymer chain.

13. A photographic element comprising a support having thereon a photographic silver halide emulsion layer in which the halide comprises at least 50 mole percent chloride, said support having thereon at least one other layer, and incorporated in at least one layer of said element a polymer prepared by reacting a dialkyl siloxane with a Water-soluble block copolymer comprising blocks of polyoxyethylene and polyoxypropylene, about 10 to about 70% by weight of said copolymer being polyoxyethylene and the average molecular weight of the polyoxypropylene in said copolymer being in the range of about 800 to about 3,000, said block copolymer having the formula:

where Y is an organic radical having a valence of x; n is an integer; x is an integer greater than 1, the values of n and x being such that the molecular weight of said copolymer exclusive of Y, E and R is in the range of about 800 to about 3,000; E being a polyoxyethylene chain constituting from about 10 to about 70% by weight, of said copolymer and R is a hydrogen atom, an alkyl group, an alkyl carbonyl group or an aryl carbonyl group.

14. A photographic element comprising a support having thereon a photographic silver halide emulsion layer in which the halide comprises at least 50 mole percent chloride, said support having thereon at least one other layer, and incorporated in at least one layer of said element, about .001 to about 1 gram, per mole of silver halide, of a polymer prepared by reacting a dialkyl siloxane with a water-soluble block copolymer comprising blocks of poly oxyethylene and polyoxypropylene, abuot 10 to about 70% by weight of said copolymer being polyoxyethylene and the average molecular weight of the polyoxypropylene in said copolymer being in the range of about 800 to about 3,000, said block copolymer having the formula:

where Y is an organic radical having a valence of x; n is an integer; x is an integer greater than 1, the values of n and x being such that the molecular weight of said copolymer exclusive of Y, E and R is in the range of about 800 to about 3,000; B being a polyoxyethylene chain constituting from about 10 to about 70% by weight of said copolymer and R is a hydrogen atom, an alkyl group, an alkyl carbonyl group or an aryl carbonyl group.

1.5. A photographic silver halide emulsion in which the halide comprises at least 50 mole percent chloride, said emulsion containing about .001 to about 1 gram, per mole of silver halide, of a water-soluble block copolymer comprising blocks of polyoxyethylene and polyoxypropylene, about 10 to about 70% by weight of said copolymer being polyoxyethylene and the average molecular weight of polyoxypropylene in said copolymer being in the range of about 800 to about 3,000, said block copolymer containing up to about 15% by weight of silicon atoms in the main polymer chain, said emulsion containing a compatible speed increasing onium salt.

16. A photographic silver halide emulsion in which the halide comprises at least 50 mole percent chloride, said emulsion containing a polymer prepared by reacting a dialkyl siloxane with a water-soluble block copolymer comprising blocks of polyoxyethylene and polyoxypropyl- 15 ene, about to about 70% by weight of said copolymer being polyoxyethylene and the average molecular weight of the polyoxypropylene in said copolymer being in the range of about 800 to about 3,000, said water-soluble block copolymer having the formula:

where Y is an organic radical having a valence of x; n is an integer; x is an integer greater than 1, the values of n and x being such that the molecular weight of said copolymer exclusive of Y, E and R is in the range of about 800 to about 3,000; E being a polyoxyethylene chain constituting from about 10 to about 70% by weight of said copolymer and R is a hydrogen atom, an aklyl group, an alkyl carbonyl group or an aryl carbonyl group, said emulsion containing a compatible speed-increasing onium salt.

17. A photographic element comprising a support having thereon a silver halide emulsion in which the halide comprises at least 50 mole percent chloride, said emulsion containing about .001 to about 1 gram per mole of silver halide, of a water-soluble block copolymer having the wherein a and b are positive integers, M is a polyethyleneoxy chain constituting about 10 to about 70% by weight N is a polypropyleneoxy chain having a molecular weight between about 800 and 3,000, and wherein x, y and n are positive integers.

18. A photographic element comprising a support having thereon a photographic silver halide emulsion in which the halide comprises at least 50 mole percent chloride, said support having thereon at least one other layer, and incorporated in at least one layer of said element, about .001 to about 1 gram per mole of silver halide of a water-soluble block copolymer having the formula:

wherein a and b are positive intergers, M is a polyethyleneoxy chain constituting about 1070% by weight of N is a polypropyleneoxy chain having a molecular weight between about 800 and 3,000, and wherein x, y and n are positive integers.

19. A photographic element comprising a support having thereon a silver halide emulsion in which the halide comprises at least 50 mole percent chloride, said emulsion containing about .001 to about 1 gram per mole of silver halide, of a water-soluble block copolymer having the following formula:

S10 )h] (B113 Jx I! wherein a and b are positive integers, M is a polyethyleneoxy chain constituting about l070% by weight of N is a polypropyleneoxy chain having a molecular weight between about 800 and 3,000, and wherein at, y and n are positive integers and the ratio of x:y is from 2:1 to 1:1.

20. An element of claim 19 in which n has a value of one to eight. I

21. A process of developing an exposed photographic silver halide emulsion in which the halide comprises at least 50 mole percent chloride, comprising imbibing into the said emulsion a block copolymer comprising blocks of polyoxyethylene and polyoxypropylene, about 10 to about by Weight, of said copolymer being polyoxyethylene and the average molecular weight of polyoxypropylene in said copolymer being in the range of about 800 to about 3,000, said block copolymer containing up to about 15 percent, by weight of silicon atoms in the main polymer chain, and reducing the exposed silver halide to silver by means of a silver halide reducing agent.

22. A photographic silver halide emulsion in which the halide comprises at least 50 mole percent chloride, said emulsion containing saponin and a block copolymer comprising blocks of polyoxyethylene and olyoxypropylene, about 10 to about 70% by weight of said copolymer being polyoxyethylene and the average molecular weight of polyoxypropylene in said copolymer being in the range of about 800 to about 3,000, said block copolymer containing up to about 15% by weight of silicon atoms in the main polymer chain.

23. A photographic silver halide emulsion in which the halide comprises at least 50 mole percent chloride, said emulsion containing saponin and a block copolymer comprising blocks of polyoxyethylene and polyoxypropylene, about 10 to about 70% by weight of said copolymer being polyoxyethylene and the average molecular weight of polyoxypropylene in said copolymer being in the range of about 800 to about 3,000, said block copolymer containing up to about 15% by weight of silicon atoms in the main polymer chain, said emulsion containing a compatible speed-increasing onium salt.

No references cited.

NORMAN G. TORCHIN, Primary Examiner.

' I. RAUBITSCHEK, Assistant Examiner. 

1. A PHOTOGRAPHIC SILVER HALIDE EMULSION IN WHICH THE HALIDE COMPRISES AT LEAST 50 MOLE PERCENT CHLORIDE, SAID EMULSION CONTAINING A BLOCK COPOLYMER COMPRISING BLOCKS OF POLYOXYETHYLENE AND POLYOXYPROPYLENE, ABOUT 10 TO ABOUT 70%, BY WEIGHT, OF SAID COPOLYMER BEING POLYOXYETHYLENE AND THE AVERAGE MOLECULAR WEIGHT OF POLYOXYPROPYLENE IN SAID COPOLYMER BEING IN THE RANGE OF ABOUT 800 TO ABOUT 3,000, SAID BLOCK COPOLYMER CONTAINING UP TO ABOUT 15 PERCENT, BY WEIGHT, OF SILICON ATOMS IN THE MAIN POLYMER CHAIN. 